Plug for tubes



. 17, v W' WAlNWRlGHT PLUG'- FOR TUBES Filed Nov. 7, 1954 @my y ffl Patented Dec. 17, 1935 UNlTED STATES PATENT OFFICE 6 Claims.

This invention relates to plugs for tubes and more particularly to plugs for boiler tubes.

One of the objects of this invention is to provide a tube plug which will be exceedingly practical in operation and durable in construction and use. Another object is to provide a device of the above nature which will be relatively inexpensive and simple to manufacture. Another object is to provide such a construction which is capable of being conveniently mounted in operative position without the need of undue alterations or adjustments to meet varying conditions. Another object is to provide a construction of the above nature which will be strong and dependable in operation and which may be installed with a.

minimum of time and expense. Another object is to provide a plug for tubes adapted to close both ends of the tube with a single operation. Another object is to provide a construction of the above nature which may be operated solely from one end of the tube.

Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists inthe features of construction, Combination of elements, and arrangements of parts as will be exemplified in the construction to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which is shown one of the various possible embodiments of this invention- Fig. 1 is a longitudinal section through a tube having a plug in accordance with the present invention inserted therein.

Fig. 2 is a similar view showing the plug in its finally adjusted position;

Fig. 3 is an end view of one of the elements embodied in the plug of the present invention.

Similar reference characters refer to similar parts throughout the several views of the drawmg.

As conducive to a clear understanding of this invention, it may here be pointed out that boilers embodying tubes are generally of two types, known as the fire tube type and the water tube type. In both types it frequently happens that a leak will occur in one of the tubes. To repair the leaky tube, it is usually necessary to draw the lire from the boiler thus to shut down its operation until repairs have been completed. The instant device contemplates the provision of a plug insertible into a leaky tube whereby such an individual tube may be shut off without the necessity for drawing the fire or discontinuing operation of the boiler. Devices for this purpose have been previously constructed, but in all such constructions there has been a uniform difficulty in providing a device which may be inserted while the boiler is in operation and which will 5 serve to seal the tube at both ends and in which the closure of both ends may be effected simultaneously from the front and accessible end of the tube. It has been a further difficulty of devices of this nature to provide means which will effectually seal the tube against any leakage whatsoever. It is an object of this invention to overcome these difculties, as well as others, all as will be apparent from the following.

Referring now to the drawing, I0 indicates the 15 front tube sheet of a conventional boiler; 1I the rear sheet thereof. A single tube such as a tube in need of repair is generally indicated at I2. It will be understood that in any boiler construction there are a plurality of such boiler tubes or iiues into any one of which the plug to be described may be introduced. Such a plug may advantageously include a hollow core generally indicated at I3, preferably constructed of steel or any other suitable material. Core I3 comprises a 25 cylindrical sleeve I4 of materially lesser diameter than the tube to be plugged and core heads I5 and I6. Core heads I5 and I6 may be formed integrally with sleeve I4 or may, as shown in the drawing, be threaded upon threaded extremities Il and I8, respectively, of said sleeve. Preferably the hub portions I5a and I6a of the core heads are formed of irregular shape, such as hexagonal, whereby the heads may be readily turned on the sleeve by a wrench or the like. Each of core heads I5 and I6 has a radially extending ange I9 and 20, respectively, whereby to define apertures or bores 2| and 22, respectively, through which bores passes an operating bolt 23, the structure and purpose of which will be'more fully described hereinafter. Each of the core heads I5 and I6 also has a cylindrically extending flange 24 and 25, respectively, the outer diameter of which is made oi a predetermined size, slightly less than the diameter of the boiler tube in which the plug is to be inserted. The end faces of flanges 24 and 25 are chamfered as indicated at 24a and 25a, respectively. Flanges I9 and 24 thus form and define a recess 26 in core head I 5 and flanges 2i! and 25 similarly 50V of. In the construction of the device, core I3 is manufactured in predetermined lengths adapted to be fitted into a boiler tube of given length.

Operating bolt 23 previously mentioned is threaded at its extremities 23d and 23h and is so positioned as to pass through apertures 2| and 22 in core heads i5 and I3 and to be centrally located with respect thereto. Such apertures are of a diameter to provide a sliding t for bolt 23, and to maintain the core and bolt in axial alignment. Gaskets 2S and 29 are respectively positioned immediately adjacent chamfered end faces 24a Aand 25a of core heads 23 and 25. These gaskets,

in the preferred embodiment of the invention are constructed preferably of asbestos or like heatresistant material and are of rectangular cross section having openings 23a and 23a, respectively positioned in the center of the periphery thereof (see Fig. l). It will be understood, however, that gaskets of any other suitable configuration may be used. Openings 28a and 23a are provided to allow a space for contraction of gaskets 28 and 29 when they are compressed in a manner and for a purpose to be more fully described hereinafter.

A pair of` gasket retaining rings e3 and 3l are positioned adjacent core heads I5 and IS, respectively. Rings 33 and 3l are preferably cylindrical in form and engage the inner surfaces of the flanges 23 and 25, and also the bottom face of gaskets 23 and 23. The external diameter of rings 3i! and 3i is slightly less than the internal diameter of the recesses 25 and 21 in the core heads formed by the anges, as above noted, whereby rings 33 and 3l may move into said recess.

Threaded on to the threaded end 23a of operating bolt 23 is a nut 32 which, prior to insertion of the plug into tube i2, serves merely to hold the apparatus in assembled relation. Nut 32 is screwed down until it engages the flange I9 and thus serves to hold the operating parts of the mechanism in assembly until tightened to its final adjusted position in a manner to be more fully described hereinafter.

Threaded on to the threaded end portion 23h of operating bolt 23 is a metallic clamping head 23, which may if desired be composed of a suitable heat-resistant material. On the inner surface of head 33 a pair of suitably spaced cam surfaces 33a and 33h are formed. Immediately adjacent head 33 and between head 33 and gasket 29 is an expansible collar 34 (see Fig. 3) composed of a plurality of segments (illustratively three) 34a, 34h and 34o, so shaped as to form a disc-like ring when positioned about operating bolt 23 (see Fig. 2 and the full line position of Fig. 3).

Collar 33 serves, when expanded in a manner to be more fully described hereinafter, to protect gasket 29 from direct contact with the name of the re to the rear of tube sheet Il, and at the same time binds against the inner tube surface to definitely locate the plug .within the tube.

Such expanding action of collar 33 is effected through a cam surface 35 formed about the outer periphery thereof and so positioned as to engage, when the device is in assembled relation, cam surface 33a of clamping head 33 and a second cam surface 35.5 also formed on ring 33 in such position as to engage the cam surface 33h of head 33. As is better shown in Fig. 2, these cam surfaces are so related that, upon actuation of clamping head 33 relatively toward the front of the boiler tube, in a manner to be hereinafter described, they will coact to cause expansible collar 33 to expand and assume the dotted line position shown in Fig. 3, at which time it will closely engage the walls of boiler tube I2.

The angular disposition of these cam surfaces 33a-35, 33h-33, with respect to each other is such, however, that even upon close contraction of clamping head 33 toward collar 34 an air space 3l will be left between collar 34 and clamping head 33. Air space 3l serves as insulation to prevent radiation of heat from the outer surface of head 33 to the segments comprising collar 34 and thence to gasket 23 and consequently provides an additional protection against the burning out of gasket 29.

It may here be noted that of the two gaskets 28 and 29, 29 will be subjected to the greatest heat due to the fact that the hottest flame is at the end of tube I2 closed by head 33. Gasket 28 being positioned at the less exposed end of the tube consequently needs no such protection as collar 34.

Portions 38 (see Figs. l and 2) are upstruck upon the back of each of segments 34a, 36h, 34o comprising collar 33. About'upstruck portions 38 a relatively frangible wire 33 is positioned and relatively tightly contracted (see Figs. l and 3). The purpose of this is to provide suitable means for holding collar 33 in its contracted position until it is desired to expand it into its protective position as shown in Fig. 2 and also in the dotted line portion of Fig. 3. When clamping head 33 is drawn towards boiler tube I2, the pressure upon cam surfaces 35 and 33 of collar 3d will cause segments 33a, 33h, 33o to move and expand radially, causing them to assume the dotted line position of Fig. 3. Such pressure will be sunicient to rupture frangible wire 3S and permit expansion of the collar to a degree limited only by the interior diameter of boiler tube I2.

A front clamping head 43 is positioned on threaded end 23a of operating bolt 23 immediately adjacent gasket 23 and its associated retaining ring 30.

Also, upon end 23a of bolt 23, but outside of head (i3, a plug finder fil (see Fig. l) which may also serve as a guard member is placed. Plug finder 4I is preferably in the form of a circular shield and has a flange [Ila extending inwardly towards head located about its outer periphery. Flange Ma extends a material distance in a lateral direction and is so arranged and positioned as to indicate by its abutment against tube sheet I0 the limit to which the plug should be inserted in tube i2. This length will be determined by the particular installation and the# length of the plug is predetermined accordingly.

Plug finder also serves as a shield to prevent the escape of flame or hot steam on to the person of the operator during insertion of the device.

A tightening nut i2 is threaded upon the outer end of bolt` 23 outside of head 33 and plug nder 3|.

In operation the plug is inserted into boiler tube i2 until flange 4m of plug nder 4U engages tube sheet i3. Tightening nut d2 may now be removed to permit removal of the iinder 40, if such is desired, and nut i2 is thereupon replaced. Said nut is now turned on the threaded end 23a of bolt 23 so as to draw the two clamping heads 33 and 'l0 towards each other and towards xed core heads E5 and Iii respectively. The inward movement of head 33 causes cam surfaces 33a and 33h to coact with cam surfaces 35 and 36, respectively, to expand the individual segments of expansible collar 3d' radially, breaking frangible and the gasket retaining rings.

wire 39,'and to compress gasket 29 against the chamfered surface 25a of core head 25. Simultaneously as head 4D is forced inwardly, gasket 28 is compressed against the chamfered surface 24a of core head 24. Gasket retaining rings 30 and 3| are moved inwardly into the recesses 25 and 2'! of core heads I5 and I6, respectively, and nut 32 is moved outwardly from its abutment with the outer face of ange I9 to a rela-tively central position in recess 26.

It will thus be seen that any expansion of gaskets 28 and 29. must be outward towards the tube l2, since movement in any other direction is restricted by the core heads, the clamping heads, The compressed gaskets thus furnish a complete seal between the ends of the core and the tube, and with core heads l5 and it and sleeve i4 forming a unitary, leak-tight structure, leakage from the ends of the tube is prevented and the tube is thus plugged and cut out effectively from operation.

Collar 35i serves to supplement the seal formed by gasket and further serves to protect gasket 2S from direct Contact with the hot flame, while air space 3? acts as further insulation to prevent undue heat from reaching gasket 29.

The plug as described is simple in construction and may be readily manufactured. The core heads may be cast with the only machining required being the threads uniting the heads with the sleeves. The majority of the parts of the plug are readily available and may be constructed inexpensively by' conventional machine practice. The parts are capable of ready assembly and when assembled may be positioned in a leaky tube in a single operation, following which the rotation of the tightening nut acts to completely seal the tube.

From the foregoing, it will be seen that there is herein provided a device which embodies the features of this invention and achieves the objects thereof including advantages of great practical importance. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment as above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

l. A plug for tubes comprising, in combination, a hollow core, a pair of opposed core heads threadedly associated therewith, the length of the core and the core heads being slightly less than the length of the tube to be plugged, said core heads being of an external diameter adapted to t within said tube and having openings axially disposed therethrough, an operating bolt passing through said openings and said core, clamping heads tted on the ends of said operating bolt, each operatively vrelated to a core head, compressible gaskets disposed between said core heads andsaid clamping heads, an expansible collar positioned between one of said clamping heads and its associated gasket, said collar comprising a plurality of segments normally forming a disc-like ring, means normally holding said segments in related assembly, and means to draw said clamping heads toward each other whereby to compress said gaskets against said core heads, and said collar against one of said gaskets, to form a huid-tight seal at each end of said core, said means being operative to render said holding means inoperative and expand said collar radially to engage the inner circumference of said tube.

2. A plug for tubes comprising, in combination', a hollow core including a pair of opposed core heads, the length of the core being slightly less than the length of the tube to be plugged, said core heads being of an external diameter adapted to t within said tube and having openings axially disposed therethrough, an operating bolt passing through said openings and said core, clamphig heads tted on the ends of said operating bolt, each operatively related to a. core head, com pressible gaskets disposed between said core heads and said clamping heads, an expansible collar positioned between one of said clamping heads and its associated gasket, said collar comprising a plurality of segments normally forming a disc-like ring, upstruck portions on the rear surface of each of said segments, frangible retaining means passed about said upstruck segments whereby to retain said segments in contracted position, and means to rupture saidA retaining means and expand said segments radially whereby to expand said collar, saidv means; being operative to draw said clamping heads toward each other to ccmpress said gaskets against said core heads to form a fluid-tight seal at each end of said core and to compress said collar against one of said gaskets to form a heat protective barrier at one end of said core.

3. A plug for tubes comprising, in combination, a hollow core including a pair of opposed core heads, the length of the core being slightly less than the length of the tube to be plugged, said core heads being of an external diameter adapted to t Within said tube and having openings axially disposed therethrough, an operating bolt passing through said openings and said core, clamping heads fitted on the ends of said operating bolt, each operatively related to a core head, compressible gaskets disposed between said core heads and said clamping heads, an expansible collar positioned between one of said clamping heads and its associated gasket, said collar comprising a plurality of segments normally forming a disclike ring, upstruck portions on the rear surface of each of said segments, a wire passed about said upstruck segments whereby to retain said segments in contracted position, and means to rupture said wire and expand said segments radially whereby to expand said collar, said means comprising operatively associated cam surfaces on the outer face of said expansible collar and the inner face of its associated clamping head, and means to draw said clamping heads toward each other whereby to compress said gaskets against said core heads to form a fluid-tight seal at each end of said core and to compress said collar against one of said gaskets to form a heat protective barrier at one end of said core.

4. A plug for tubes comprising, in combination, a hollow core including a pair of opposed core heads, the length of the core beinga slightly less than the length of the tube to be plugged, said core heads being of an external diameter adapted to fit within said tube and having openings axially disposed therethrough, an operating bolt passing through said openings and said core, clamping heads fitted on the ends of said operating bolt, each operatively related to a core head, compressible gaskets disposed between said core heads and said clamping heads, an expansible collar positioned between one of said clamping heads and its associated gasket, said collar comprising a plurality of segments normally forming a disclike ring, upstruck portions on the rear surface of each of said segments, a wire passed about said upstruck portions and operative to retain said segments in contracted position, and means to rupture said wire and expand said segments radially whereby to expand said collar, said means comprising a plurality of cam surfaces on the outer face of said expansible collar and a plurality of cam surfaces on the inner face of its associated clamping head, the angular disposition of said cam surfaces on said collar to said cam surfaces on saidclamping head being such that upon close contraction and coaction of said cam surfaces an air space is left between said expansible collar and said clamping head, and means to draw said clamping heads toward each other whereby to compress said gaskets against said core heads to form a Huid-tight seal at each end of said core and to compress said collar against one of said gaskets to form a heat protective barrier at one end of said core.

5. A plug for tubes comprising, in combination, a hollow core including a sleeve and a pair of spaced core heads threaded thereto whereby tial ange of an external diameter adapted to t within the tube to be plugged, said flanges intersecting to form a recess, an operating bolt passing through said sleeve and core heads, an assemblylnut threaded 0n said operating bolt and disposed in said recess and operative to abut a face of said radial flange, clamping heads each operatively related to a core head, compressible gaskets disposed between said core heads and said clamping heads, and means cooperating with said bolt to draw said clamping heads toward each other whereby to compress said gaskets against the ends of said circumferential flanges to form a uid-tight seal at each end of said core.

6. A plug for tubes comprising, in combination, a hollow sleeve, a pair of opposed core heads threadedly associated with said sleeve whereby to permit a relative variation of the length of said plug within predetermined limits without disassembly of said plug, clamping heads positioned adjacent said core heads, compressible gaskets disposed between said core heads and said clamping heads and means to draw said clamping heads inwardly towards said core heads to compress said gaskets and seal the ends of said tube.

WALTER WAINWRIGHT. 

